Wound dressing membrane

ABSTRACT

Disclosed is a method for producing an intra-oral dental bandage membrane and/or therapeutic membrane containing therapeutic agent. Actinic light is used to polymerize the membrane composition material to fix the composition in position locked with rigid dental structure such as teeth. The polymerizable substance is manipulated and shaped in a fluid state and then set, as shaped very rapidly in situ. Also disclosed is a new treatment membrane that in a preferred form is a non-symetrical oligomer that is a urethane polyacrylate.

RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.935,455, filed Nov. 26, 1986, now U.S. Pat. No. 4,813,875, issued Mar.21, 1989, which is in turn a continuation-in-part of Ser. No. 636,136,filed July 31, 1984, now abandoned.

BACKGROUND OF THE INVENTION

The present invention is concerned with bandages and other treatmentmembranes for mammals, especially for dental applications in the oralcavity or mouth to be mechanically retained in position by the teeth inhumans. The treatment membrane is contemplated to have medicalapplications beyond dentistry.

Periodontal diseases and other dental diseases and difficulties affect asignificant percentage of the population, causing defects in bonysupportive structure of teeth and deterioration of the attachement ofthe tooth to soft tissue. It is often necessary to conduct one or moreforms of surgery to correct anatomical defects which are the consequenceof the disease, or to eliminate the microbiological milieu which isresponsible for the progression of the disease. Thus, surgicallyremoving soft tissue or bone may be a treatment to allow better accessfor plaque removal by the patient; or tooth substance and adjacenttissue may be surgically removed to eliminate the microbiologicalinfection; or teeth and adjacent tissue may be surgically removed toprepare for dentures or as a consequence of carious destruction of thenatural dentition. In many of these cases a dressing is desirably placedto protect the defect or wound site, for example, protecting soft tissueand sutures after surgery.

Present dressings are typified by combinations of metallic oxides andorganic acids that are mixed together immediately prior to use, mostfrequently as two pastes which react in-situ to form hard, brittle,opaque compounds. Frequently one of the reactants is weakly acidic, acarboxylic acid or a phenolic compound, e.g. eugenol, or the like. Theweak salts that form and are the structural basis of the compound arehydrolytically unstable. Saliva may leach these reactants as theyhydrolyze. In due course the products crumble and disintegrate and thepatients swallow or expectorate the fragments. The leached structuralproducts frequently are unpleasant tasting and are otherwiseundesirable.

Another class of compounds relies on the reaction of calcium sulfatehemihydrate, dispersed in a water permeable mixture of precured polymerand solvent. Sometimes the compounds contain inert filler, and waterfrom the saliva is used to react with the calcium sulfate hemihydrate toform gypsum. This reaction occurs relatively slowly, and frequently theproducts are disintegrated before they can carry out their requisiteprotective function.

Yet another class of prior known materials is the combination of apolymer, polyethyl methacrylate and a solvent mixture frequentlycomprising a plasticizer such as esters of phthalic acid and ethanol.The plasticized pseudoelastomer which forms as the polymer solvates haspoor elastic properties and develops slowly. The progression toadequately high viscosity requires from 10 to 30 minutes. Nopolymerization occurs. As the alcohol and plasticizer are eluted in timein the mouth the mixture becomes increasingly hard.

Each of these materials depend on the reaction, (for purposes of thisdiscussion the solvation of a polymer by a solvent is classified as areaction), between two or more previously separated components which arecombined together and allowed to harden in-situ. In the first case,metal ions and organic carboxylic acids or phenolic compounds react, inthe second case calcium sulfate hemihydrate and water (saliva); and inthe third case, polymer powder and solvent.

It is an object of the present invention to provide methods andmaterials that overcome the deficiencies of the known dental wounddressings: to provide new methods and materials that provide treatmentmembranes that are long lasting and resist destruction between dentalappointments, and are easy and quick to apply with good retentiveproperties and are useful for wound dressings, stents and othertreatment purposes.

Another object of the present invention is to obviate the need for twoseparate components, and to obviate the time delay and inconveniencewhich are a consequence of mixing and having them react at theirpretimed schedule within the mouth.

Another object is to provide a treatment membrane material that is fluidand has adequate manipulation time after placement to allow adapting thetreatment membrane material to the site to be treated and then providesa means for quickly setting the fluid to convert the fluid to a solid.

Yet another object is to permit prepackaging of a bandage, especially ofthe wound or periodontal dressing type, within a syringe from which thewound dressing can be extruded inter-dentinally for mechanicalretention, and directly upon a wound surface as required.

Another object is the provision of a bandage which may be mechanicallyretained by etched patterns in the enamal of teeth.

A further object of the invention is to provide a treatment membranethat is pigmented so as to be aesthetically less noticeable when inplace in the oral cavity (mouth) of a patient.

Another object is to provide a treatment membrane that is translucent orclear, allowing inspection of the wound site without removal of themembrane.

Yet a further object is to provide a treatment membrane in a preferredform that is resilient and non hardening and thereby gentler to softtissue with which it is in contact, an aid to patient comfort and aidsin the longevity of the treatment membrane in the hostile environment ofthe oral cavity.

A further object is to provide a treatment membrane that is moistureresistant and non-fouling.

A still further object of the invention is to provide a treatmentmembrane that yields a continuing dose of therapeutic material over aperiod of time.

SUMMARY OF THE INVENTION

The present invention in a preferred embodiment of one of its aspects isa method for producing an intra-oral bandage using actinic light topolymerize a composition to fix the composition in position between theteeth, around a tooth, or affixed to an acid etched portion of a tooth,or in similar association with other rigid dental structure. In onepreferred embodiment of the invention in one of its aspects, apolymerizable substance is provided that can be manipulated and shapedin a fluid state for a substantially prolonged period of time and thenset as shaped very rapidly in situ when desired, forming a bandage. Thesetting is preferably carried out through the initiation of a chemicalreaction by actinic light, especially light within the visible lightrange.

By another aspect of the invention, a treatment membrane is providedthat is a polymeric membrane substantially free of leachable undesirabletoxic substance and amenable to inclusion of therapeutic leachablesubstances.

By yet another aspect of the present invention, the polymeric membraneincludes a therapeutic substance preferably distributed substantiallyuniformly throughout its mass, from the surface to its innermostdimension.

By a further aspect in certain preferred embodiments, a new treatmentmembrane is provided having medical applications beyond dentistry.

DEFINITIONS

A "treatment membrane", which is the broader concept of the presentinvention, includes both the method of providing a bandage and themethod of holding therapeutic agent in position. The treatment membranecan be exclusively a bandage, exclusively a therapeutic agent treatmentyielder or both combined. "Bandage" as used in the present patentapplication means a flexible strip, band or piece used to cover,strengthen, or compress: included are strips or patches used especiallyto dress and/or bind up wounds in the oral cavity. "Dental bandage"means a bandage used in the oral cavity or in association with dental."Wound dressing" as used in this patent application means a materialapplied to cover a lesion.

By "rigid dental structure" it is meant to include natural teeth as wellas other structure, such as bridge work, crowns, veneers and solidimplants attached to bone structure and the like. "Fluid" as used inthis application shall be understood to include not only very fluidmaterials that pour and run readily, but also viscous and gelatinousmaterials and materials that have paste and putty consistencies, all ofwhich are fluid or are readily flowable when pressure is applied causingthem to assume permanent new shapes before polymerization as compared tosolid elastomeric materials which flow when subjected to force butreturn to substantially their original shape when the pressure isreleased. "Set", means to change from a fluid state to a solid statewhich may be in the form of a rigid solid or an elastomeric solid. By"therapeutic agent" it is meant any agent applied or provided as atreatment of disease or disorders and these include desensitizing andanesthetic agents which aid in relieving discomfort, antiseptic agentswhich are preventative agents, as well as antibiotics and the like. Bytissue it is meant both soft tissue, such as mucosa, and hard tissuesuch as bone and teeth.

The treatment membrane of the present invention is to be distinguishedfrom sealants used to seal pits and fissures and filling materials usedto fill cavity perparations. However, the methods of the treatmentmembranes of the present invention are intended to include thepositioning of the claimed materials for treating areas of the teethadjacent to the gum or soft tissue with desensitizing agents and thelike. Also the treatment of the oral cavity to treat for microorganismsthat cause dental caries is included within the perview of the presentinvention, within the scope of a treatment membrane. By "dentist" it ismeant to include those surgeons who work in the area of the mouth andsurrounding structure, orthodontist, periodontist, dental auxiliariessuch as hygienist and the like.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention in one preferred embodiment is a method ofproducing a treatment membrane in situ in the oral cavity of a mammal.To produce the treatment membrane a fluid polymerizable compositioncomprised of polymerizable organic compound and photoinitiator isapplied as a fluid composition in sufficient juxtaposition to rigiddental structure to provide a mechanical locking with the rigid dentalstructure upon the polymerization or setting of the fluid polymerizablecomposition. The setting of the composition mechanically locks the setcomposition to the rigid dental supporting structure producing thetreatment membrane in situ in the oral cavity, that is to sayinter-orally. The enamel of teeth may be etched with phosphoric acidsolution to retain the bandage wholly or in part.

The polymerizable organic compound is preferably an oligomer, morepreferably a urethane acrylate oligomer with a reaction functionality ofat least two. The photoinitiator is preferably an actinic lightinitiator activated in the visible light range. The setting of thepolymerizable compound is in response to engagement of a surface of thefluid polymerizable composition by actinic light. The fluidpolymerizable composition is preferably a one-component composition thatis shelf stable when stored actinic light free. The composition ispreferably applied from a syringe and caused to flow to completelysurround at least one tooth to provide mechanical locking, preferably indirect contact with the tooth. The setting of the composition would thenbe with the fluid polymerizable composition completely surrounding thetooth and forming in one preferred embodiment a bandage, in anotherpreferred embodiment a therapeutic membrane and in yet another preferredembodiment a bandage that is a therapeutic membrane.

In one preferred embodiment therefore, a method is provided forproducing an inter-oral drug delivery device in situ in a mammal. Inthis method the fluid polymerizable composition preferably includes thetherapeutic substance homogeneously mixed throughout and the setting orcuring of the polymerizable composition does not preclude thetherapeutic substance from diffusing from the treatment membrane, butrather provides a treatment membrane structure from which thetherapeutic substance is leachable or metered into the oral cavity for aperiod, preferably a period of at least one week.

DETAILS OF FLUID POLYMERIZABLE COMPOSITIONS OF THE PRESENT INVENTION

Organic prepolymers that have a reaction functionality of at least twoare suitable for constituting the polymerizable organic compound used inthe present invention. Preferred are the urethane polyacrylateprepolymers. Examples of urethane polyacrylate prepolymers that arepreferred include: The adduct of 1 mole of polytetramethylene glycol orpolyethylene glycol and their polymers with 2 moles of hexamethylenediisocyanate or another difunctional isocyanate to which is added 2moles of hydroxy ethyl or hydroxypropyl methacrylate; the adduct of 1mole of polytetramethylene glycol and 2 moles of an isocyanatoethylmethacrylate; and the adduct of 1 mole of trimethyl hexamethylenediisocyanate and 2 moles of hydroxypropylmethacrylate.

One, more preferred urethane polyacrylate prepolymer, is one having thefollowing general formula:

    R.sub.1 --A]R.sub.2

R₁ is ##STR1## R₂ is ##STR2## R₁ and R₂ each independently preferablyhave from 5 to 100 C, more preferably 5 to 15 C and most preferably 6 to11 C.

R₃ is H, alkyl, sub alkyl, aryl, sub aryl, F, CN. (The term sub as usedin this application means substituted, which means that at least one nonC or H atom would be present or a radical such as a benzene ring wouldbe present. By arcylic it is meant any pendent acrylic radical, bydiacrylic it is meant a radical or a compound with two pendent acrylicradicals.)

R₃ may be the same or different in each position.

R₃ is preferably methyl.

R₄ is a divalent hydrocarbon radical or divalent sub hydrocarbon radicaland may be straight or branched chain or cyclic or a combinationthereof. By cyclic it is meant to include aromatic and heterocycliccompounds.

R₄ preferably has from 2 to 100 C, more preferably

R₄ is an aliphatic radical having from 2 to 100 C, more preferably 2 to10 C and most preferably 2 to 6 C.

A is any polyurethane oligomer. (By poly as used in this application itis meant two or more. By oligomer it is meant a molecular weight of atleast 250, more preferably 400 and most preferably 600 or more. The termbackbone as used in this application means the structure of the oligomerbetween the two urethane groups closest to the terminal ends of themolecule). R₄ may be the same or different in each position.

The presently more preferred composition, which is an important aspectof the present invention, is A is --R₅ ] X --R₆ ].

R₅ and R₆ are each independently divalent hydrocarbon radicals ordivalent sub hydrocarbon radicals and may be straight or branched chainor cyclic or a combination thereof and may also be siloxane or subsiloxane radicals.

R₅ and R₆ preferably have from 2 to 100 C, more preferably R₅ and R₆ arealiphatic radicals having from 2 to 100 C, more preferably 2 to 10 C.

R₅ and R₆ may be the same or different.

X is a polyurethane and R₅ --X and R₆ --X are joined by a urethanelinkage.

X may broadly contain any hydrocarbon or sub hydrocarbon radical and maybe straight or branched chain or cyclic or a combination thereof and mayalso be one or more of the following radicals: siloxane, sub siloxane,sulfone, etc., but is preferably a polyether or a polyester or mixturethereof, most preferably X is a polyether and the polyether radical isstraight chain, of course as a polyurethane.

It should be clear from the above general formula that it is notconsidered critical to the present preferred prepolymer in its broaderaspects what the radical --A] may be so long as it is a hydrocarbon orsub hydrocarbon and a polyurethane. Beyond this the person skilled inthe art would tailor the radical to achieve such characteristics as theymay choose. However, the asymmetry of R₁ and R₂ are a central feature ofthe present invention and are believed to constitute a significantadvance in the art of urethane polyacrylates. The particularly preferred--A] radical, especially with both R₅ and R₆ joined to X by a urethanelinkage with X being of substantial molecular weight and both R₅ and R₆of low molecular weight, is of special preferred merit, especially inthe more preferred embodiments of the present invention.

R₁ is a radical preferably formed by reacting a hydroxy acrylate with anisocyanate group on a prepolymer polyurethane oligomer and is drawn toinclude the urethane group contributed by the isocyanate.

R₂ is a radical contributed entirely by an isocyanato acrylate when theisocyanato acrylate is reacted with a hydroxy group on a prepolymerpolyurethane oligomer.

In --R₅ ] X --R₆ ], R₅ would be the terminal radical in the prepolymerpolyurethane oligomer when the terminal urethane group has been drawn aspart of R₁. For clarity of explanation, in Example 1 this would be thetrimethyl hexamethylene radical from trimethyl hexamethylenediisocyanate and would include the other urethane group contributed bythe diisocyanate. R₆ would be the oxyalkylene residue of the 1,4 Butanediol.

The more preferred compound has the formula: ##STR3## wherein R₇ isAlkylene, sub alkylene.

x is 10 to 100.

The method of producing the preferred non symmetrical urethanepolyacrylate prepolymers is revealed in detail in Example 1 and withgreater explanation in U.S. Ser. No. 935,455 the contents of which areincorporated herein by reference.

Mixtures of the above given exemplary prepolymers and other similaroligomers may be used as the sole polymerizable ingredient; or the fluidpolymerizable composition may include diluent comonomers such as--otherlower viscosity diluent monomers and oligomers, for example polyethyleneglycol dimethacrylate, butylene glycol dimethacrylate and the like. Alldiluent monomers are characterized as having low volatility andtoxicity.

Additional exemplary prepolymers for use in the present inventioninclude: polysiloxanedimethacrylates, polyorganosilylenes--forexample--polydimethyl-silylene-co-phenylmethylsilylene, polycarbonateurethane dimethacrylates, Ethoxylated bisphenol A dimethacrylate,2,2-Bis[4-(3-methacryloxy-2 -hydroxypropoxy)phenyl]propane (BISGMA), and2,2-Bis[4-(2-methacryloxy-2 -methylethoxy)phenyl]propane (BISIPMA).

The dental treatment composition material of the present invention inits preset, fluid form is preferably substantially stable againstassuming a permanent remembered form when stored actinic light free. Thecomposition is preferably stable when stored as a single one-componentmaterial for a long period of time actinic light free, preferably beingstable for at least two months, more preferably six months, and mostpreferably for one year or more. By one-component, it is meant that thetreatment membrane material can be stored in the exact form that it willbe used in by the dentist, so that the dentist preferably does not needto do anything other than mold the composition to the surface (surfaces)that are to be protected, treated or retain the treatment membrane andthen cure the treatment membrane material by exposing it to actiniclight to form the treatment membrane.

The preferred embodiment providing a shelf-stable storable treatmentmembrane material is one having a photoinitiating system. Thephotoinitiating system may be one of many known in the art to promotepolymerization of unsaturated acrylic groups when activated by actiniclight of the appropriate wavelengths, strength and length of exposuretime. Such systems include, but are not limited to camphoroquinone andother alpha-beta diketones, alone or with reducing agents, such assecondary and tertiary amines, compounds known to be accelerators forphotopolymerization of acrylates upon irradiation by visible light.Materials such as benzoin and benzoin methyl ether which are known to bephotopolymerization initiators utilizing light in the near UV portion ofthe electromagnetic spectrum are operable to cure the presentlypreferred polymers, but UV light is considered generally undesirable inmost instances because of possible interactions with living tissue.

The actinic light activated photopolymerizable composition is for healthand safety reasons preferably one that can be expeditiously cured usinglight filtered to limit the wave lengths to the visible light range ofapproximately 360-600 nanometers. More preferably the curing is carriedout with the greater portion of the light being within the 400-500nanometer range.

The amount of photopolymerization initiator or sensitizer and the typesare selected with due consideration to the intensity of the intendedlight source and the activating wavelength(s) and their capacity toinitiate polymerization. Photoinitiators, for example, camphoroquinone,are preferably used in concentrations between 0.001 and 10% by weight ofthe polymerizable resin present, more preferably between 0.01 and 5%.Accelerators for the photoinitiation for example, tertiary amines,including, for example, methyldiethanolamine, diethanolamine,triethanolamine, 4-ethyldimethylaminobenzoate, or4-dimethylaminobenzonitrile may be used. These are preferably used inamounts of between 0.001 and 10% by weight of the polymerizable resinpresent, more preferably between 0.01 and 5%.

The dental treatment membrane is preferably a viscous liquid, or it canbe modified with fillers to result in more viscous pastes or evenputties. It is important in some cases that these materials be moldableusing the gloved finger of a dentist or an instrument so that thematerial ma be adapted between the teeth, or pressed against a tooth toobtain retention by the acid micro etched patterns upon enamel. Theaddition of solid fillers is a means to facilitate this, but they mustbe chosen to have suitable optical characteristics so as not tointerfere with the transmission of actinic light through the material toinitiate polymerizatiion. The filler particles should have size andsurface area appropriate to effect the desired viscosity change.

Generally the fillers are chosen primarily for viscosity modificationbut they may also be used to influence the bonding properties of thetreatment membrane as well. Reinforcing fillers may also be used toimprove the strength of the treatment membrane. Typically reinforcingfillers will have particle sizes of less than 1 micron and appropriatesurface treatments to enhance bonding with the polymerizing oligomericpolymer. Preferred reinforcing fillers have a surface area of at least50 square meters per gram and are exemplified by pyrogenically-producedsilicon dioxide, silicic acid hydrogels dehydrated so as to maintaintheir structure, silicon dioxide, and precipitated silicon dioxide, withpreferred particle sizes between 0.001 and 1.0 microns. The nonreinforcing fillers may be larger in size, for example up to 250microns, and they also may not be surface treated. Typical fillersinclude calcium carbonate, fused quartz powder, powdered calciumsilicaluminate, titanium dioxide, zirconium silicate, aluminum silicate,crystobalite, feldspar, etc. Preferred fillers include silicon dioxidesuch as fused quartz. The fillers may be ground or formed by a varietyof means including polymerization as microspheres to provide particulatepowdered filler of preferred sizes between 1 and 250 microns, dependingon the application. Particles of individual average sizes of 1 and 100microns are especially preferred.

All of these fillers; but especially the reinforcing fillers, can haveorganosilyl groups on their surface if they have been pretreated, forexample, with dimethyl-halogen silanes, for example by reaction ofaqueous silica sol with organo halogensilanes, or have been renderedhydrophobic in some other way. Mixtures of different fillers can beused. Non-reinforcing fillers may in some instances be used atconcentrations of up to about 80%, more preferably limited to less than60% by weight based on the total weight of the fluid treatment membranecomposition material. Reinforcing fillers may be appropriately used inthe compound in an amount of from 1% to 80% by weight, based on thetotal weight of the fluid treatment membrane composition material, morepreferably 10-40% and most preferably 15 to 30%. Preferred overallfiller contents are from 5 to 95% more preferably 20 to 90% and mostpreferably for some applications 40 to 85% by weight based on the totalcomposition weight. An important consideration is that the amount andthe type of filler is so selected that actinic radiation may passthrough the mass to cause polymerization throughout, but the filler neednot match the refractive index of the resins exactly.

Dispersants and surface active agents may be included to aid in thedispersion and combining of the fillers and pigments and better bondingwith the polymerizable matrix oligomers. Alkyl benzensulfonyl titanatesare preferred dispersing agents for fillers in the free radicalinitiated polymerizable resin. A preferred alkyl benzensulfonyl titanateis neoalkoxy, tridodecylbenzenesulfonyl titanate (Titanium IV neoalkoxy,tris(dodecylbenzene)sulfonato). The titanate is preferably present in anamount of 0.001 to 2% by weight of the total composition, morepreferably 0.005 to 1% and most preferably 0.01 to 0.5%.

Another important embodiment of the present invention provides treatmentmembranes which serve as a repository and long term dispenser of a widerange of therapeutic agents useful in treating mammals. Thesetherapeutic agents may be incorporated into the treatment membrane ofthe present invention by mixing or encapsulation.

Examples of therapeutic agents include those for treating infection bysuch organisms as Streptococcus mutans (which is causally implicated indental caries), or A. actinomycetemcomitans and B. gingivalis (which arecausally linked with periodontal disease), or the like. Exemplary ofthese therapeutic agents are the following examples arranged bystructure and clinical use:

1. Antiseptics and Germicides

a. ethanol and isopropanol

b. iodine preparations

(1) iodine, U.S.P.

(2) Providine-Iodine

(3) iodoform

(4) thymol iodine

c. thimerosal (Merthiolate)

d. oxidizing agents

(1) urea peroxide

(2) chlorine dioxide

(3) benzoyl peroxide

e. Phenolic Compounds

(1) eugenol, U.S.P.

(2) Guaiacol (2-Methoxyphenol)

f. Quaternary Ammonium Compounds

(1) Benzalkonium Chloride. U.S.P.

(2) Benzethonium Chloride (Phemerol Chloride)

2. Non-antibiotic Antimicrobials

a. Chlorhexidine

b. Silver Nitrate (1%)

c. silver sulfadiazine (1%)

3. Antibiotics

a. Penicillins

b. Tetracyclines

c. Erythromycins

d. Cephalosporins

e. NBH (1% neomycin, 1% bacitracin. 0.5% hydrocortisone)

f. metnanidasole

4. Antifungal agents

a. triacetin

b. ciclopirox olamine

c. clotrimazole

d. griseofulvin

e. miconazole nitrate (2%)

f. Castellani Paint (basic Fuchsin, Phenol, Resorcinol, acetone,alcohol.

g. amphotericin B

h. Nystatin

5. Steroidal Antiinflammatory agents

a. Triamcinolone acetonide (0.1%)

6. Non-steroidal antiinflammatory agents

a. salicylates

b. indomethacin

c. ibuprofen

d. fluoribuprofen

e. 2-[3-(1,1-dimethyl)-5-methoxyphenyl]oxazolo[4.5b]pyridine

7. Antiviral agents

a. triamcinolone

8. Non-fluoride tooth desensitizing agents

a. strontium chloride 10%

b. sodium citrate 1.5%

c. Potassium Nitrate 5%

9. Wound healing agents & anti-collagenase (protease) agents

a. fibronectin (plasma)

b. tripeptides

c. short chain peptides up to 20 amino acids in length which exhibitwound healing or anticollagenase (antiprotease) or antielastaseactivity.

Therapeutic agents can be included, such as those that treat caries byproviding locally high concentrations of remineralizing chemicals, asexemplified by those yielding calcium ion, fluoride ion, and phosphateion. Such therapeutic agents are exemplified by sodium fluorophosphate,tricalcium phosphate, sodium fluoride, calcium fluoride, etc.; orantiseptic compounds, for example, chlorhexidine.

Therapeutic agents may be included for sedating the tooth byapplications of locally high concentrations of topical anesthetic ormetal cations, hydroxyl ions, and the like, which can obturate thedentinal tubuli to avoid sensitivity. Such therapeutic agents would beexemplified by benzocaine, strontium chloride, calcium hydroxide, andthe like. The therapeutic agents useful in the present invention may besolid or liquid, inorganic or organic.

It will be understood that the aforementioned exemplary therapeuticmaterials, or their equivalents, are preferably uniformily dispersedthroughout a treatment membrane compositiion to provide for diffusion ata rate determined solely by their dispersion through the polymerizedcomposition. Alternatively the therapeutics may first be combined withother ingredients separately to provide for their microencapsulation ina first solid uniformly or, they may be dispersed through a first slidand comminuted to form particles of, preferably, less than 250 micronssize, which then are dispersed through the fluid polymerizablecomposition to further regulate their diffusion. For example, the agentsmay first be microencapsulated within gelatin or dispersed withinmicroparticles of, e.g. polyvinyl alcohol. The preferred prepolymerizedmicroparticles are preferably composed of polymer, chosen from the groupof water soluble and water dispersible polymers and mixtures thereof.The microparticles act as reservoirs for the therapeutic agent. Themicroparticles preferably should be less than 250 microns in size.

It will be understood that these carrying or accompanying substancescontaining or accompanying the therapeutic agent would in preferredembodiments be uniformly dispersed throughout the fluid treatmentmembrane composition material from the outer surface throughout theinner thicknesses of the bandage. After curing, in preferredembodiments, these dispersed domains of relatively high therapeuticconcentration may aid in the metering and more uniform leaching of thetherapeutic agent into the treatment area over a period of time. Thecarrying or accompanying substance may also aid with the generaldispersion and retention of the therapeutic agents within thepolymerizable composition.

Other formulation auxiliaries may also be included in the treatmentmembrane material. Organic polymers, for example polyvinyl pyrrolidoneor methacrylate polymer powder, polyvinyl alcohol and the like, may beused as fillers, extenders and plasticizers. Stabilization of thesecompositions against premature polymerization may be achieved by theaddition of hydroquinone, catechol, and other similar well-knownpolymerization inhibitors for the polymerization of (meth) acrylatecompounds. Other optional ingredients include pigments and flavoringsubstances. Still other plasticizers may be included, for example,siloxanes, phthalates, glycerides, and other materials known to the art.Such plasticizers are generally added to alter the hydrophobicity, thesoftness or hardness of the composition, its viscosity or tackiness,etc.

A preferred treatment membrane has an elongation in tension of at least1%, more preferably 3% and most preferably 10%; a strain in tensil of atleast 5% more preferably 10% and most preferably 20%; and a modulus ofelasticity of at least 100 psi, more preferably 200 psi and mostpreferably 400 psi.

The preferred treatment membranes of the present invention when used forperiodontal wound dressings have the desirable property of resistingingress of healing tissue into the membrane itself and thereby lendsitself to easy removal from soft tissue of the oral cavity. Such anespecially preferred treatment membrane is comprised of thenon-symmetrical urethane polyacrylate polymer described in thisinvention and shown, for example, in Example 1. Except where teeth aredeliberately acid eteched for retention of the treatment membrane thepreferred treatment membrane material provides for ready release,non-adhering characteristics relative to rigid structures in the oralcavity, both natural dentition and artificial, after curing. This offersthe advantage of easy removal to avoid damaging protected structuresunintentionally, especially soft tissue structure in the process ofrepair. The preferred treatment membrane material also is substantiallynon-toxic in use and non-allergenic.

The preferred treatment membrane material can be readily cured in directcontact with living mammalian tissue.

DETAILED DESCRIPTION OF APPLYING THE METHOD OF THE PRESENT INVENTION

The treatment membrane formulation or material is preferably prepackagedin a syringe. The treatment membrane material is then applied directlyfrom the syringe to the surfaces to be provided with the treatmentmembrane. The fluid material is then shaped and molded with aninstrument or the finger to position it in relation to the structure tobe provided with the treatment membrane and also with relation to anystructure that will hold the bandage in position. Preferably adisposable glove is used and it may be lubricated with a thin film of amaterial such as vaseline, lanolin or cold cream or the like. Preferablythe rigid dental structure that will hold the treatment membrane inposition is cleaned and dried before application of the treatmentmembrane material to it. Dental enamel may be micro-etched, for examplewith 30% phosphoric acid by procedures well known to the art, for betterintraoral retention. The treatment membrane material is cured byexposing it to actinic light. The material can be checked for coverageand position and additional material may be added and cured as desired.In the case of preferred treatment membrane materials, the additionalmaterial bonds to the cured original treatment membrane and is noteasily dislodged therefrom.

Not only can the treatment membrane serve as a bandage covering an areato keep food, fluids, and other debris from contaminating the area, butin instances where a wound is not severe or where conservative surgeryhas been done the bandage may act as a stint to maintain closureeliminating the need for sutures. An example of when this might beparticularly applicable would be in the case of conservative periodontalsurgery, i.e., flap currettage, gingival currettage without reflectionof a gingival flap, or a modified Widman Flap procedure where themucoperiosteal flap has not been fully reflected to expose the alveolarcrest. In such selected instances, proper positioning of the fluidbandage may act as a wound closure device, reducing or totallyeliminating the need for non-absorbable or absorbable suture placement.The fluid bandage, when polymerized, could act as a wound closure stent,as well as protective bandage.

On occasion it may also be desirable to build up the treatment membranein layers by placing individual coatings of fluid bandage material inposition and curing them. Preferably the layers would be in thicknessesof about 0.5 to 3 mm and might be applied three or four coatings orlayers deep, curing each in turn. This procedure can in some instancesprovide superior wedging and positioning of the treatment membrane inthe embrasures between and around the teeth or locking with other rigiddental structures. Additions may be added to the cured bandage at anytime. For example, if a portion of the bandage does become dislodged forsome reason, the cured fluid bandage material does not have to betotally removed and replaced, as is currently commonly required.Increments of the fluid bandage material may be applied to the existingintra-oral bandage segment and cured, thus giving an augmented bandagewhich is then fully functional and cohesive as a single unit.

In its preferred form, the method includes aspects of the materials thatcan perform the needed actions for preferred performance of thepreferred methods of the present invention. The preferred method doesnot require pre-mixing of the composition before it is used. Thecompositions are preferably flowable, deformable and substantially freeof any shape memory prior to activation by actinic light so that thecomposition can be formed to the desired shapes of treatment membranesagainst both the rigid and soft tissue surfaces of the oral cavity.

The one-component composition of the present invention can be packagedin various ways including the preferred preloaded syringes, from whichthe dentist can express the material directly onto the soft or hardtissues of the oral cavity. The composition can also be preloaded into adental tray which can be placed by the dentist directly into the mouthof the patient, or it can be preloaded into a collapsible tube fromwhich the dentist can squeeze the material onto a dental tray shaped toforce the material against the teeth. The tray can be of a material thatpasses actinic light. An important point is that the container packageoverwrap be metal, or otherwise be opaque to actinic light, or bepackaged in such a manner as to protect the composition of the inventionfrom actinic light prior to use by the dentist. Of course, the traywould usually be configured to adapt the material around a given area,not to provide full coverage of teeth as when taking a dentalimpression.

The actinic light is preferably visible light from a source such as thePRISMETICS® lite and PRISMA-LITE® polymerization units of the L. D.Caulk Company, which produces visible light with a band of wavelengthsbetween 400 and 500 nanometers and an energy output of approximately 400milliwatts per square centimeter from the tip of the unit's light guide.The polymerization time can vary depending on the intensity andwavelength of the light used and the quantity of material to bepolymerized, but is preferably two minutes more preferably one minute,given the above conditions.

The composition of the present invention is stable against prematurepolymerization. The composition is preferably non-toxic in use in theoral cavity; stable in storage for at least six months as aone-component composition when actinic light free; and assumes apermanent memory when exposed to light filtered to limited wavelengthswithin the visible light range for one minute to a depth of at leastthree millimeters.

The invention is further illustrated by the following examples:

EXAMPLE 1 Resin 1 Preparation

A preferred isocyanatoethyl methacrylate urethane methacrylate oligomerelastomer prepolymer compound was prepared according to the followingformulation

    ______________________________________                                        Polypropylene glycol (MW 4000)                                                                          834.6 g                                             Voranol 2140 (Dow Chemical)                                                   Trimethylhexamethylene diisocyanate                                                                      87.7 g                                             (Thorson Chemicals)                                                           Stannous octoate           0.50 g                                             Hydroxyethyl methacrylate (Rohm & Haus)                                                                  27.1 g                                             1,4 Butanediol (BASF)      18.7 g                                             Isocyanatoethyl methacrylate                                                                             30.8 g                                             ______________________________________                                    

The procedure was as follows:

In theory, one mole of polypropylene glycol (2 equivalents of hydroxy)are reacted with two moles of trimethylhexamethylene diisocyanate (4equivalents of isocyanate) employing the stannous octoate as catalyst.

The polypropylene glycol was charged into a 2 liter reacter. Stirringand dry air flow through the reactor was begun. The stannous octoate wascharged to the reactor and allowed to stir in. Then thetrimethylhexamethylene diisocyanate was added to the glycol catalystmixture dropwise using a separatory funnel. The addition was done atroom temperature and was controlled to keep the temperature below 50° C.Addition was complete after 30 minutes. The contents were allowed tostir for 30 minutes more. Samples were taken and titration was done todetermine isocyanate content. Isocyanate was found to be 1.9% whichindicated complete reaction of the polypropylene glycol andtrimethyhexamethylene diisocyanate. Then the 27.1 grams of HEMA wereadded all at once to the reactor contents which were at a temperature ofabout 40° C. The contents were allowed to stir for 45 minutes. Thentitration samples were taken and the isocyanate content determined to be0.95%. This indicated complete reaction of the HEMA with the isocyanateterminated prepolymer leaving 1 equivalent of isocyanate sites forreaction with 1,4 butane diol. At this point 18.7 grams of 1,4 butanediol were added to reactor contents all at once and allowed to stir infor 2 hours. The temperature of the reactor continued between 40° and50° C. for this procedure. At the end of 2 hours the isocyanatoethylmethacrylate was added dropwise to the reactor using a separatoryfunnel. This addition took approximately 30 minutes. Stirring wascontinuous until the next morning to be sure all the free isocyanate wasreacted. Then the pot contents were unloaded.

Bandage Preparation

A visible light curable bandage of the following formulation wascompounded by a double planetary mixer at reduced pressure. Theingredients were added in the order listed in the abscence of visiblelight.

    ______________________________________                                        Resin of EXAMPLE 1          373.5 g                                           Camphorquinone               0.76 g                                           4-Dimethylaminobenzonitrile  3.49 g                                           Butylated Hydroxy Toluene    0.163 g                                          Titanium IV neoalkoxy, tris (dodecylbenzene)                                                               0.30 g                                           sulfanato (Ken React LICA 09 from Kenrich                                     Petrochemicals, Inc.)                                                         Silanated/ground Quartz (mean particle                                                                    464.8 g                                           size of 10-15 microns)                                                        fumed silica (Aerosil R-972 from Degussa)                                                                 155.0 g                                           Rocket red fluorescent pigment (Dayglo)                                                                    0.214 g                                          ______________________________________                                    

The composition was irradiated for 10 seconds using the Prismetics®light earlier described. A sample of material 20 mm thick was coveredwith a sheet of clear Mylar about 1 mil thick. The sheet was in directcontact with the sample. The light was directly engaged against thesheet of Mylar. The material cured to a rubbery solid to a depth of 13mm. The uncured composition was removed by wiping.

Water sorption and solubility measurements were taken on the curedmaterial with the results given below.

    ______________________________________                                        *1 Week Water Sorption (mg/cm.sup.2)                                                                 0.61                                                   **1 Week Water Solubility (%)                                                                        0.20                                                   ______________________________________                                         *Performed as in American Dental Association (ADA) Spec. #27.                 **Performed as in ADA Spec. #8 except specimens were left in distilled        water for one week instead of 24 hours.                                  

The composition is non-tacky in use and bonded to acid etched toothenamel by molding the pasty material against the tooth with a glovedfinger prior to polymerizing to set using a Prismetics® light.

EXAMPLE 2 Resin 2 Preparation

A urethane dimethacrylate was prepared according to the followingformulation:

    ______________________________________                                        Hydroxy propyl methacrylate (HPMA)                                                                      59.18%                                              Trimethylhexamethylene diisocyanate (TMDI)                                                              40.75%                                              Stannous octoate           0.05%                                              Methyl ether hydroquinone  0.02%                                              ______________________________________                                    

Procedure: The hydroxy propyl methacrylate stannous octoate, and methylether hydroquinone were weighed into a dry two liter reactor. Stirringand dry air flow through the reactor were begun. The reactor contentswere heated to 50° C. and was continually stirred for 30 minutes to forma homogenous solution. The TMDI was weighed into a beaker and pouredinto a 250 ml. addition funnel where it was next added dropwise to thereactor. The drop rate was monitored to keep the temperature between50°-60° C. The next morning, a sample was taken and found to be free ofresidual diisocyanate. Then the reactor contents were unloaded.

Resin 3 Preparation

A polyether urethane dimethacrylate was prepared according to thefollowing formulation:

    ______________________________________                                        Pluracol 628 (polypropylene                                                                          93.61%                                                 glycol mw 4,000)                                                              Isocyanatoethyl methacrylate (IEM)                                                                    6.34%                                                 Stannous octoate        0.05%                                                 ______________________________________                                    

Procedure: The Pluracol 628 and stannous octoate were weighed into a drytwo liter reactor. Stirring and dry air flow through the reactor werebegun. The IEM was weighed into a beaker and poured into a 250 ml.addition funnel where it was added dropwise to the reactor. The additionof IEM was done keeping the temperature below 50° C. Addition took 30minutes. After addition the contents were allowed to stir 36 hours at atemperature between 40°-50° C. Then a sample was taken, found to be freeof residual isocyanate, and the reactor contents unloaded.

Bandage Preparation

A visible light bandage of the following formulation was compounded by adouble planetary mixer at reduced pressure:

    ______________________________________                                        *Resin mixture (Resin 2-20 parts and                                                                    241.3 g                                             Resin 3-80 parts)                                                             Camphorquinone             0.5 g                                              4-Dimethylaminobenzonitrile                                                                              2.2 g                                              Butylated Hydroxy toluene  0.244 g                                            Silanated Ground Quartz (Mean particle                                                                  565.1 g                                             size of 10-15 microns)                                                        fumed silica (Aerosil R-972)                                                                            188.1 g                                             Neoalkoxy, tridodecylbenzene-sulfonyl                                                                    2.5 g                                              titanate (Ken React LICA 09)                                                  Rocket Red Fluorescent Pigment (Dayglo)                                                                  0.260 g                                            ______________________________________                                         *Resin 2 and Resin 3 were combined first and stirred for 30 minutes in a      double planetary mill.                                                   

The composition was irradiated for 1 minute using the procedure ofExample 1. The material cured to flexible solid that was substantiallystiffer than the solid produced in Example 1.

EXAMPLE 3-5

A series of treatment membrane samples were prepared based upon thecomposition of Example 1.

Varying amounts of sodium fluoride powder sieved to less than 250microns was added to the bandage composition of Example 1 to producecompositions 3, 4, and 5. These were made into discs having a diameterof 20 mm and a thickness of 1 mm by filling a Mylar backed stainlesssteel ring, inserting a small piece of nylon string, smoothing thesurface, and curing for 1 minute on the top side only with a GEPhotoflood lamp (EBV-NO. 2). The top surface of the disc were leftuncovered. The weight of each specimen was then recorded to the nearest0.1 mg. The discs were prepared in 3 replications and extractedindividually in deionized water by suspension in 11 ml. of the water.Each day the micrograms of fluoride extracted were measured using an ionfluoride sensitive ion electrode in conjunction with a Fisher Accumet pHmeter (model 825 mp). After the daily measurement was taken, the oldwater was discarded and fresh water was added to the specimens so thatthe daily extraction data was accurate. On weekends the data wascollected for the three days. Original concentrations of sodium fluorideand extraction data are presented as such in the table below:

                                      TABLE 1                                     __________________________________________________________________________    Micrograms Released                                                           Time (Days)                                                                   Ex.                                                                              % NaF                                                                             1   2   3  4  5-7 8  9  10 11  12-14                                                                            15 16                                __________________________________________________________________________    3  1%  30.7                                                                              18.1                                                                              16.1                                                                             15.7                                                                             37.3                                                                              11.0                                                                              9.5                                                                              8.5                                                                              8.1                                                                             19.6                                                                               5.2                                                                             11.                               4  2%  78.7                                                                              41.3                                                                              32.7                                                                             29.9                                                                             71.0                                                                              20.2                                                                             17.9                                                                             16.1                                                                             15.9                                                                             39.0                                                                              11.8                                                                             25.                               5  5%  193.1                                                                             100.0                                                                             79.4                                                                             65.9                                                                             132.7                                                                             44.0                                                                             39.6                                                                             34.7                                                                             34.0                                                                             95.9                                                                              31.5                                                                             82.                               __________________________________________________________________________

EXAMPLES 6-8

A series of treatment membrane samples were prepared based upon thecomposition of Example 2, except that sodium fluoride (-250 μm) wasadded. The original concentrations and extraction data (see examples 3-5for testing procedure) are given in Table 2.

                                      TABLE 2                                     __________________________________________________________________________    Micrograms Released                                                           Time (Days)                                                                   Ex.                                                                              % NaF                                                                             1  2   3   4   5-7                                                                              8  9  10 11 12-14                                                                             15 16                                __________________________________________________________________________    6  1%   80.8                                                                            51.8                                                                              46.6                                                                              38.9                                                                               90.5                                                                            18.0                                                                             11.0                                                                              6.7                                                                             4.6                                                                              6.0 1.1                                                                              1.                                7  2%  132.4                                                                            83.6                                                                              73.3                                                                              66.3                                                                              157.9                                                                            32.5                                                                             21.4                                                                             13.5                                                                             7.9                                                                              9.7 1.41                                                                             2.                                8  5%  287.3                                                                            175.7                                                                             137.6                                                                             122.4                                                                             324.3                                                                            97.4                                                                             85.7                                                                             74.2                                                                             61.2                                                                             121.2                                                                             25.3                                                                             28.                               __________________________________________________________________________

EXAMPLE 9

The treatment membrane formulation of Example 3 was loaded into a 3 ccsyringe having a reservoir diameter of 10 mm and length of 55 mm and anoutlet length of 12 mm and smallest diameter of 3 mm. The syringe wasmade of polypropylene.

The treatment membrane material was applied to the upper right quadrantbuccal and lingual tissue surfaces of a human by the followingprocedure:

1. Disposable gloves were lubricated with thin film of K-Y jelly(Johnson & Johnson, Inc.)

2. The cap was removed from the syringe and the VLC perio dressing wasextruded onto the juncture of the hard and soft tissue including theinterproximal areas of the buccal surfaces.

3. The material was muscle molded and/or contoured with a lubricatedfinger or instrument to the tissues. Care is taken to avoid placement onocclusal contacting areas of the teeth.

4. The material was cured by exposing each area for 20-40 seconds withthe Prismetics lite held 10 mm from the material. Curing was completedin 1 minute.

5. Occlusion and coverage of the material was checked. Additionalmaterial was added and cured for 10 seconds. The additional material wasbonded and could not be dislodged from the first.

6. The material was then applied to the lingual surfaces as in step 2.

7. The material was contoured to the tissues with the lubricated gloves.

8. The material was cured as in step 4.

9. Occlusion and coverage of the material were checked. Both weresatisfactory.

The product was tough, adherent, and could not be removed without somedifficulty. The product was aesthetically pleasing and comfortable towear. It was retained in place for seven days and then removed. Visualinspection with the unaided eye showed minimal adherence of bacterialplaque and minimal staining except by agents known to impart stain onexisting dental restorative materials, such as coffee, tea and tobacco.However, this staining did not materially adversly effect the estheticsof the material.

EXAMPLE 10-12

A series of treatment membrane compositions were prepared by mixing thebelow given ingredients in a motorized mortar at ambient conditions. Allof the solids were added first and mixed until uniform in appearance.The liquids were premixed and then one half of the mixed liquids wereadded to the mortar and mixing was continued until smooth uniformmixture was obtained. The remaining liquid was then added to the mortarand mixing was continued until the mixture was homogeneous.

    ______________________________________                                        Example #              10     11                                              ______________________________________                                        Urethane dimethacrylate                                                                              56.5   56.5                                            (Plex 6661 from Rohm AG)                                                      triethylene glycol     28.2   28.2                                            dimethacrylate                                                                polyvinyl pyrrollidone mw 24000                                                                      7.4    0                                               methylene blue         .01    .01                                             Camphorquinone         .46    .46                                             dimethylamine ethyl benzoate                                                                         .18    .18                                             silicon dioxide        3.1    3.1                                             butylated hydroxytoluene                                                                             .05    .05                                             sodium fluoride        4.13   4.13                                            strontium chloride hexahydrate                                                                       0      3.97                                            ______________________________________                                    

The treatment membrane compositions were then prepared as test samplesby placing 1/2 gram of each composition into a polyethylene container 12mm in diameter, and 8 mm deep and filled the container to about 1/2full.

The fluoride ion therapeutic agent release is expressed as micro gramsof fluoride ion per 1 cm² of surface area of the specimen. The fluorideion concentration was determined using a fluoride electrode (Phillips)with a pH meter reading in m V (Metrome). The specimen was stirred at aconstant rate in 50 ml of distilled water, and readings taken at 0.5, 1,2, 4, 6, and 24 hr. The water was then exchanged for fresh distilledwater every 24 hr. and the readings were taken and the water replacedwith fresh water at the next 24 hr. period.

    ______________________________________                                                                          24   48  72  96   130                       Ex.  1/2 hr 1 hr   2 hr 4 hr 6 hr hr   hr  hr  hr   hr                        ______________________________________                                        10   40     60     70   105  125  298  98  20  20   836                       11   32     52     67    90  103  163  49  13  18                              12*  5      5     10    33   60  118  98  16  15   360                       ______________________________________                                         *Example 12 is Duraphat ® shellac, a commercial shellac composition       sold as a tooth coating. The Duraphat shellac sample was tested in the        same manner as described in Examples 10 and 11.                          

EXAMPLES 13-15

A comparison was made between current inter-oral wound dressings and thewound dressing or bandage of the present invention.

Example 13 shows the results of testing the fluid bandage compositionmaterial of Example 1. Example 14 shows the results of testing ofcurrent commercial material sold as a periodontal dressing under thebrand name Coe-Pack hard and fast set supplied by Coe Laboratories,Chicago, Ill. Example 15 shows the results of testing another currentcommercial material sold as a periodontal dressing under the brand namePerio-Putty by Cadco.

Depth of cure was measured using the method described in example 1.

Consistency was measured as follows: A tube calibrated to deliver 0.5ml. was packed with the materials (for example 14 the uncured materialwas used; for examples 15 and 16 the freshly mixed material was used)and extruded onto a sheet of polyethylene. Another sheet of polyethylenecovered the material. A glass plate weighing 76 grams plus a 500 gramweight was then placed on top of the polyethylene and material for 30seconds. Then the weight and plate was removed and the diameter of thedisc was measured to the nearest millimeter. The average of threedeterminations is reported.

Strain in compression was measured according ADA Spec. 19. The specimenwas cured for 40 seconds with the Prismetics® lite using the 14 mm tip.The test was started one minute after irradiation was complete.

Tear strength, Elongation in tension, Strain in tension, and Modulus ofelasticity in tension were all tested on an Instron (Model 1123 withhydraulic grips) and a Microcon II microprocessor.

The specimens were prepared by filling a mold prepared for the purpose.The mold was stainless steel and in the shape of the Roman Numeral I.The top and bottom cross ends were 16 mm across and the web numberbetween was 5 mm across in the same direction. The cross ends were each13 mm in vertical dimension and the web member was 22 mm in verticaldimension. The depth of the mold or thickness of the sample was 1.5 mm.

Specimens were prepared for example 13 by filling mold with uncuredmaterial, placing a Mylar strip (1 mil thick) on the top and bottom,pressing flat, and curing for 30 seconds under the photoflood lamp (GEEBV-No. 2). Then the specimen were demolded and placed in distilledwater at 37° for 24 hours before testing. Specimens for example 14 wereprepared by mixing equal lengths of base and accelerator for 30 secondsand then packing mold with material. Mylar strips were placed on top andbottom of the mold, stainless steel plates were also placed top andbottom, and the whole assembly was clamped and put into a 37° C. ovenfor 12 minutes. Then the assembly was removed from the oven, thespecimen was demolded and placed in distilled water at 37° C. for 24hours before testing. Specimens for example 15 were prepared by mixingone small scoop of catalyst and one large scoop of base (as permanufacturer's directions) for 30 seconds. The mold was packed andclamped as in Example 14 and placed in a 37° C. oven for 15 minutes.Then the assembly was removed, specimen was demolded, and placed indistilled water at 37° C. for 24 hours before testing. Six specimens ofeach material were prepared.

Testing was done using a crosshead speed of 10 mm/min. and a load of 5Kg.

Tear strength was calculated as follows: ##EQU1##

Elongation was determined at the rupture of the specimen.

Strain in tension was calculated by dividing the elongation by the gagelength (22 mm) times 100.

Modulus of Elasticity was calculated using the automatic mode for whichan overall slope is computed as a least-mean-square fit over all thedata in the constant-slope region. The formula used was: ##EQU2##

    ______________________________________                                                 Example 13 Example 14 Example 15                                     ______________________________________                                        Work Time  Unlimited    5-8 Min.   4-6 Min.                                   Set Time   Upon irradiation                                                                           8-10 Min.  12 Min.                                               in 20-40 sec.                                                      Depth of   13-14 mm     --         --                                         Cure (10 Sec)                                                                 Consistency                                                                              24 mm        20 mm      20 mm                                      Strain in  2.0%         1.16%      0.28%                                      Compression                                                                   Tear Strength                                                                            325.5 PSI    118.9 PSI  87.1 PSI                                   Elongation in                                                                            9.2 mm       0.4 mm     0.10 mm                                    Tensile                                                                       Strain in  40.2%        1.8%       0.45%                                      Tension                                                                       Modulus of 930 PSI      0 Not      0 Not                                      Elasticity              Measurable Measurable                                 ______________________________________                                    

While throughout this application the present invention of a treatmentmembrane has been described with respect to dental application, it willbe obvious to those skilled to the art that there would be many generalmedical applications for which the invention would be well suited. It istherefore intended that the invention be understood to also includeapplicability in such uses.

While in accordance with the patent statutes, what is considered to bethe preferred embodiment of the invention has been described, it will beobvious to those skilled in the art that numerous changes andmodifications may be made therein without departing from the inventionand it is therefore aimed in the apended claims to cover all suchequivalent variations as fall within the true spirit and scope of theinvention.

It is claimed:
 1. A method of producing an elastomeric bandage in situin the oral cavity of a mammal comprising:applying a fluid actinic lightpolymerizable composition comprising polymerizable organic compound andvisible actinic light initiator to tissue in the oral cavity in need ofthe protection of a bandage, flowing said fluid polymerizablecomposition in direct contact with rigid dentition to provide a directmechanical locking with said rigid dentition upon the setting of saidfluid polymerizable composition, causing said fluid polymerizablecomposition to set by exposing said polymerizable composition to actiniclight to form a elastomeric dental bandage mechanically locked to saidrigid dentition.
 2. The method of producing a dental bandage in the oralcavity of claim 1 wherein said polymerizable organic compound has areaction functionality of two, said setting is at least in part inresponse to engagement of a surface of said fluid polymerizablecomposition by actinic light and said setting forms an elastomeric oralcavity dental bandage.
 3. The method of producing a dental bandage inthe oral cavity of claim 2 wherein said fluid actinic lightpolymerizable composition retains its fluid form for a period of atleast two months as a one component composition when stored actiniclight free, is applied from a syringe and is flowed to completelysurround at least one tooth in direct contact with said tooth to providesaid mechanical locking and is set completely surrounding said at leastone tooth.
 4. The method of producing a dental bandage in the oralcavity of claim 2 wherein said fluid actinic light polymerizablecomposition retains its fluid form for a period of at least two monthsas one component composition when stored actinic light free is appliedfrom a syringe and is flowed to a wedged position in an embrasurebetween two teeth in direct contact with said teeth to provide saidmechanical locking and is set in wedged position in said embrasurebetween said two teeth.
 5. The method of producing a dental bandage inthe oral cavity of claim 2 wherein said polymerizable organic compoundis an oligomer that is a urethane acrylate and said actinic lightinitiator is activated by actinic light having a wave length of about360-600 nm.
 6. The method of producing a dental bandage in the oralcavity of claim 1 wherein said fluid actinic light polymerizablecomposition comprises therapeutic substance homogeneously mixedthroughout, and after said setting said therapeutic substance isleachable in said oral cavity for a period of at least one week.
 7. Themethod of producing a dental bandage in the oral cavity of claim 1,wherein said polymerizable organic compound comprises a compound of thegeneral formula:

    R.sub.1 --A]R.sub.2

R₁ is ##STR4## R₂ is ##STR5## wherein R₃ is H, F, CN or methyl R₃ may bethe same or different in each position R₄ is a divalent hydrocarbonradical or benzene substituted divalent hydrocarbon radical having 2-100carbon atoms and may be straight or branched chain or cyclic or acombination thereof, and is a polyurethane oligomer having a molecularweight of at least 600 said method comprising(a) cleaning and dryingsaid rigid dental structure; (b) thereafter flowing said fluidpolymerizable composition directly against said rigid dental structure,(c) curing said fluid dental polymerizable composition while it isdirectly engaged with said rigid dental structure to mechanically lockit therewith.
 8. The method of producing a dental bandage in the oralcavity of claim 7 wherein said organic compound comprises a compositionof the general formula: ##STR6## R₇ =Alkylene, and x=10 to 100 wherein.9. The method of producing a dental bandage of claim 8 wherein saidfluid actinic light curable composition includes said polymerizableorganic compound in an amount of about 5 to 95% by weight of the totalweight of said fluid actinic light curable composition; said actiniclight initiator in an amount of about 0.001 to about 10% by weight ofsaid polymerizable organic compound; and filler in an amount of about 5to 95% by weight of the total weight of said fluid actinic light curablecomposition.
 10. The method of producing a dental bandage in the oralcavity of claim 1 wherein said fluid actinic light polymerizablecomposition comprises therapeutic agent.
 11. A method for producing aninteroral drug delivery device in situ in a mammalcomprising:positioning a fluid polymerizable composition comprisingpolymerizable organic compound, polymerization initiator and therapeuticagent inter-orally by delivering said composition from a syringe intodirect contact with rigid dentition, modeling said fluid polymerizablecomposition to conform to the shape and position of said right dentitionwhile it is interoral, and polymerizing said fluid polymerizablecomposition in situ by the application of visible actinic light toproduce an elastomeric drug delivery device which is mechanicallyinterlocked with said rigid dentition.
 12. The method of claim 11,wherein said fluid polymerizable composition comprises solid leachablematerial chosen from the group consisting of microcapsules,prepolymerized polymer microparticles including therapeutic agent andmixtures thereof having a particle size of less than about 250 micronschosen from the group consisting of water soluble and water disperableprepolymerized polymers and mixtures thereof.
 13. The method of claim11, wherein said polymerizable organic compound comprising comprises acompound of the general formula:

    R.sub.1 --A]R.sub.2

R₁ is ##STR7## R₂ is ##STR8## wherein R₃ is H, F, CN or methylR₃ may bethe same or different in each position R₄ is a divalent hydrocarbonradical or benzene substituted divalent hydrocarbon radical having 2-100carbon atoms and may be straight or branched chain or cyclic or acombination thereof, and is a polyurethane oligomer having a molecularweight of at least 600;wherein in said method said modeling includesforming said fluid polymerizable composition in sufficient juxtapositionto rigid dental structure to provide a mechanical locking with saidrigid dental structure upon the polymerizing of said fluid polymerizablecomposition, and said polymerizing in situ bringing about a locking withsaid rigid dental structure, and said method comprising cleaning anddrying said rigid dental structure before positioning said fluidpolymerizable composition.
 14. A method of claim 13 wherein said fluidpolymerizable includes said polymerizable organic compound in an amountof about 5 to 95% by weight of the total weight of said fluid actiniclight curable composition; said actinic light initiator in an amount ofabout 0.001 to about 10% by weight of said polymerizable organiccompound; and filler in an amount of about 5 to 95% by weight of thetotal weight of said fluid actinic light curable composition.
 15. Themethod of claim 11 wherein said therapeutic substance is homogeneouslymixed throughout said fluid polymerizable composition and after saidsetting is leachable in said oral cavity for a period of at least oneweek.
 16. A method of producing a dental bandage in the oral cavity of amammal comprising:acid etching the enamel of at least one tooth in theoral cavity applying a fluid visible actinic light polymerizablecomposition comprising a polymerizable organic compound and actiniclight initiator to damaged tissue in the oral cavity, flowing said fluidpolymerizable composition in sufficient juxtaposition to said at leastone acid etched tooth to provide attachment of said polymerizablecomposition on setting thereof, setting said fluid polymerizablecomposition to attach to said at least one tooth and producing said oralcavity dental bandage.
 17. The method of claim 16 in which saidattachment of said polymerizable material to said at least one acidetched tooth is a mechanical locking thereof.
 18. The method of claim 16in which said attachment of said polymerizable material to said at leastone acid etched tooth is an adhesive bonding thereto.